Mr.  G.  W.  Stow  on  South-African  Diamond- gravels.      235 
not  only  have  fragments  of  similar  iron  been  met  with  in  the  basalt, 
but  the  basalt  itself,  upon  being  examined,  is  found  to  contain 
minute  particles  of  metallic  iron,  identical  in  chemical  composition 
with  that  of  the  large  masses  themselves,  whilst  some  of  the  masses 
of  native  iron  are  observed  to  enclose  fragments  of  the  basalt. 
As  the  chemical  composition  and  mineralogical  character  of  these 
masses  of  native  iron  are  quite  different  from  those  of  any  iron  of 
terrestrial  origin,  and  altogether  identical  with  those  of  undoubted 
meteoric  iron,  Professor  jSordenskjold  regards  them  as  aerolites, 
and  accounts  for  their  occurrence  in  the  basalt  by  supposing  that 
they  proceeded  from  a  shower  of  meteorites  which  had  fallen  down 
and  buried  themselves  in  the  molten  basalt  during  an  eruption  in 
the  Miocene  period. 
Notwithstanding  that  these  masses  of  metallic  iron  were  found 
lying  on  the  shore  between  the  ebb  and  flow  of  tide,  it  has  been 
found,  upon  their  removal  to  Stockholm,  that  they  perish  with  ex- 
traordinary rapidity,  breaking  up  rapidly  and  falling  to  a  fine  powder. 
Attempts  to  preserve  them  by  covering  them  with  a  coating  of 
varnish  have  as  yet  proved  unsuccessful ;  and  it  is  actually  proposed  to 
preserve  them  from  destruction  by  keeping  them  in  a  tank  of  alcohol. 
2.  "  On  the  Geology  of  the  Diamond-fields  of  South  Africa."  By  Dr. 
John  Shaw,  of  Colesberg.  Communicated  by  Dr.  Hooker,  F.R.S.,F.G.S. 
The  author  described  the  general  structure  of  the  region  in  which 
diamonds  have  been  found.  He  considered  that  the  diamonds  origi- 
nally belonged  to  some  metamorphic  rock,  probably  a  talcose  slate, 
which  occupied  the  heights  during  a  late  period  of  the  "  trappean 
upheaval"  to  which  he  ascribed  the  origin  of  the  chief  physical 
features  of  the  country.  This  upheaval  was  followed  by  a  period  of 
lakes,  the  traces  of  which  still  exist  in  the  so-called  "  pans"  of  the 
region ;  the  Yaal  river  probably  connected  a  chain  of  these  lakes ; 
and  it  is  in  the  valley  of  the  Yaal  and  the  soil  of  the  dried-up  "  pans" 
that  the  diamonds  are  found.  The  author  referred  also  to  the 
frequent  disturbance  and  removal  of  the  diamantiferous  gravels  by 
the  floods  which  prevail  in  these  districts  after  thunder-storms. 
3.  "On  the  Diamond-gravels  of  the  Yaal  River,  South  Africa." 
By  G.  "W.  Stow,  Esq.,  of  Queenstown,  Cape  Colony.  Communicated 
by  Prof.  T.  Rupert  Jones,  F.G.S. 
The  author  described  the  general  geographical  features  of  the 
country  in  which  diamonds  have  been  found,  from  Mamusa  on  the 
south-west  to  the  headwaters  of  the  Yaal  and  Orange  Rivers.  He 
then  indicated  the  mode  of  occurrence  of  the  diamonds  in  the  gravels, 
gravelly  clays,  and  boulder-drifts  of  the  Yaal  valley,  near  Pniel, 
including  Hebron,  Diamondia,  Cawood's  Hope,  Gong  Gong,  Klip 
Drift,  Du  Toit's  Pan,  and  other  diggings.  By  means  of  sections,  he 
showed  the  successive  deepenings  of  the  Yaal  valley  and  the  gradual 
accumulation  of  gravel-banks  and  terraces,  and  illustrated  the  enor- 
mous catchment  area  of  the  river-system,  with  indications  of  the 
geological  structure  of  the  mountains  at  the  headwaters.  The  spe- 
cimens sent  by  Mr.  Stow,  as  interpreted  by  Prof.  T.  R.  Jones,  showed 
that  both  igneous  and  metamorphic  rocks  had  supplied  the  material 
